Function of magnetic control car instrument, spinning bike instrument: 1. TIME: Press the MODE button to display the time. This value indicates the duration of the exercise. 2. SPEED: Press the MODE key to show the speed. This value reflects the current exercise speed. 3. DISTANCE: Press the MODE key to reveal the distance. This value measures the distance covered during the exercise. 4. CALORIE: Press the MODE button to display calories. This value represents the energy expended during the workout. Works with headphone-like cables. Both speedometer and heart rate connection are made via 3.5 mm female jacks on the back of the monitor - adapters (NOT INCLUDED) may be necessary if the device features female jacks (rare cases). [Compatible with Most Indoor Exercise Bikes] - for stationary bikes with headphone-like connection tips. E.g. many bike models by Sunny, L-Now, Pleny, Faafuu - compatible with 95% of domestic models. [Heart Rate Monitoring Feature] works with bikes equipped with pulse sensors (usually 2 x metal pieces on the handle). Re-wiring may be necessary for specific models. [2 x AAA Batteries Not Included - Required] Batteries are NOT included. Product size: 108x163mm LCD size: 48x23mm Colour: white Material: plastic Package Contents: 1 * Monitor Speedometer W/ Heart Rate Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item to vary slightly from the actual product. The allowed measurement error is +/- 1-3cm.